Paris (AFP)
The birth in 2018 of "GMO babies" in China had raised an outcry.
Two years later, an international commission delivers its recommendations: it is necessary to be certain that the genetic modification of human embryos for medical reasons does not cause undesirable effects, before considering to have recourse to it.
This commission, made up of 18 experts from different disciplines, does not reject the principle of genetic modification in humans.
But it intends to provide a framework and red lines not to be crossed for countries which decide to take this path.
"The modification of the genome transmissible to the progeny is not yet ready to be tested in a safe and effective way in humans", warn the experts in a press release accompanying their report.
And any possible authorization of its use will have to be done "gradually and carefully", judge Richard Lifton, president of Rockefeller University (United States) and co-president of this commission, created by the American academies of medicine and sciences and the British Royal Society.
It was formed after a Chinese researcher, He Jiankui, caused a global scandal in November 2018 by announcing the birth of the first genetically modified babies, twins whose DNA he says have modified to make them resistant to the AIDS virus. with which their father was infected.
A third child with altered DNA was also subsequently born, according to the official China New news agency.
- Unanimity against it -
He Jiankui says he used the CRISPR-Cas9 technique, which has revolutionized genomic medicine in recent years.
These "genetic scissors" can replace parts of the genome, like correcting a typo on a computer.
Much less expensive and easier to use than the techniques used up to now, the dissemination of this technique has revived the debate on the implications that its application would have in humans.
If He Jiankui's experiment had been unanimously opposed, particularly because of the potential unintended consequences that the introduction of genetic mutations, even targeted ones, can have, the very principle of modifying the human genome for medical reasons divides scientists and doctors.
In March 2019, research luminaries had called for a moratorium on genome modification techniques, but this proposal was freshly welcomed by other scientists: they feared a halt to research that is sparking enormous hopes in the treatment of genetic diseases.
The recommendations of the international commission relate to the modifications of the DNA of gametes (ova and spermatozoa), eggs or human embryos intended to lead to a successful pregnancy - and not only for research purposes -.
These changes are particularly sensitive because they can be passed on to subsequent generations.
- "Prevention of serious diseases" -
If some countries decide to allow these transmissible genome modifications, this will need to be preceded by "rigorous pre-clinical research" to ensure that the mutations introduced do not lead to unintended negative consequences.
"A criterion which is not yet fulfilled by any existing genome editing technology", underline the 18 experts.
Another essential prerequisite: to organize "a broad debate on the social and ethical questions" implied by these techniques.
And initially, it will be necessary to limit their use to "the prevention of serious diseases caused by the mutation of a single gene", such as cystic fibrosis, sickle cell disease, thalassemia or Tay-Sachs disease, a neuro disease. - hereditary degenerative which results in particular in severe intellectual deficit and blindness.
When there is no alternative, "the transmissible modification of the human genome could represent an important option to allow future parents with a known risk of transmitting a genetic disease to have a child who is genetically related to them non-carrier. of this disease, "the report said.
These opinions should feed into the work of the WHO advisory committee on human genome editing, which is due to issue its own recommendations by the end of 2020.
© 2020 AFP